Structure-function analyses of metal-binding sites of HypA reveal residues important for hydrogenase maturation in Helicobacter pylori
Fig 2
H. pylori ΔhydB has no detectable hydrogenase activity and wild-type urease activity.
(A) Cell lysates of the wild-type (WT) strain, urease mutant strain (ΔureB), and hydrogenase mutant strain (ΔhydB) were used to measure hydrogenase activity using a methyl viologen assay. The rate at which H2 was oxidized (in μmol/min) was obtained using the slope of absorbance at A578 nm, which was normalized to the amount of total protein in the cell lysate (in μg), and normalized against the activity of the WT strain to obtain percent hydrogenase activity. Three biological replicates were tested for each strain, and the mean and standard deviation are graphed. (B) Cell lysates of the WT, ΔureB, and ΔhydB strains were used to measure urease activity using ammonia production in a phenol-hypochlorite assay. The specific urease activity was normalized to the amount of total protein in the cell lysate (in μg), and normalized against the specific activity of the WT strain to obtain relative urease activity. Three biological replicates were tested for each strain, and the mean and standard deviation are graphed.